Migration with zero-copy-send currently has it's limitations, as it can't
be used with TLS nor any kind of compression. In such scenarios, it should
output errors during parameter / capability setting.
But currently there are some ways of setting this not-supported scenarios
without printing the error message:
!) For 'compression' capability, it works by enabling it together with
zero-copy-send. This happens because the validity test for zero-copy uses
the helper unction migrate_use_compression(), which check for compression
presence in s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS].
The point here is: the validity test happens before the capability gets
enabled. If all of them get enabled together, this test will not return
error.
In order to fix that, replace migrate_use_compression() by directly testing
the cap_list parameter migrate_caps_check().
2) For features enabled by parameters such as TLS & 'multifd_compression',
there was also a possibility of setting non-supported scenarios: setting
zero-copy-send first, then setting the unsupported parameter.
In order to fix that, also add a check for parameters conflicting with
zero-copy-send on migrate_params_check().
3) XBZRLE is also a compression capability, so it makes sense to also add
it to the list of capabilities which are not supported with zero-copy-send.
Fixes: 1abaec9a1b2c ("migration: Change zero_copy_send from migration parameter
to migration capability")
Signed-off-by: Leonardo Bras <leob...@redhat.com>
---
migration/migration.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/migration/migration.c b/migration/migration.c
index 78f5057373..c6260e54bf 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1274,7 +1274,9 @@ static bool migrate_caps_check(bool *cap_list,
#ifdef CONFIG_LINUX
if (cap_list[MIGRATION_CAPABILITY_ZERO_COPY_SEND] &&
(!cap_list[MIGRATION_CAPABILITY_MULTIFD] ||
- migrate_use_compression() ||
+ cap_list[MIGRATION_CAPABILITY_COMPRESS] ||
+ cap_list[MIGRATION_CAPABILITY_XBZRLE] ||
+ migrate_multifd_compression() ||
migrate_use_tls())) {
error_setg(errp,
"Zero copy only available for non-compressed non-TLS
multifd migration");
@@ -1511,6 +1513,17 @@ static bool migrate_params_check(MigrationParameters
*params, Error **errp)
error_prepend(errp, "Invalid mapping given for block-bitmap-mapping:
");
return false;
}
+
+#ifdef CONFIG_LINUX
+ if (migrate_use_zero_copy_send() &&
+ ((params->has_multifd_compression && params->multifd_compression) ||
+ (params->has_tls_creds && params->tls_creds && *params->tls_creds))) {
+ error_setg(errp,
+ "Zero copy only available for non-compressed non-TLS
multifd migration");
+ return false;
+ }
+#endif
+
return true;
}
--
2.37.1
